//
//  FGOAuthViewController.swift
//  飞哥大微博
//
//  Created by huangfei on 2017/6/8.
//  Copyright © 2017年 huangfei. All rights reserved.
//

import UIKit
import SVProgressHUD

/// 通过 webView 加载新浪微博授权页面控制器
class FGOAuthViewController: UIViewController {

    private lazy var webView = UIWebView()
    
    override func loadView() {
        view = webView
        view.backgroundColor = UIColor.white
        
        // 取消滚动视图
        webView.scrollView.isScrollEnabled = false
        
        // 设置代理
        webView.delegate = self
        
        // 设置导航栏
        title = "登录新浪微博"
        
        // 导航栏按钮
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "返回", target: self, action: #selector(close), isBack: true)
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "自动填充", target: self, action: #selector(autoFill))
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 华加载授权页面
        let urlString = "https://api.weibo.com/oauth2/authorize?client_id=\(FGAppKey)&redirect_uri=\(FGRedirectURL)"
        // 1> URL 确定要访问的资源
        guard let url = URL(string: urlString) else {
            return
        }
        // 2> 建立请求
        let request = URLRequest(url: url)
        // 3> 加载请求
        webView.loadRequest(request)
    }
    
    /// MARK: - 监听方法 
    // 关闭控制器
    @objc func close() {
        SVProgressHUD.dismiss()
        dismiss(animated: true, completion: nil)
    }
    
    // 自动填充 - WebView 的注入，直接通过 js 修改 “本地浏览器中缓存的页面内容”
    @objc private func autoFill() {
        // 准备 js
        let js = "document.getElementById('userId').value = '649536839@qq.com';" + "document.getElementById('passwd').value = 'huangfei123';"
        
        // 让 webView 执行 js
        webView.stringByEvaluatingJavaScript(from: js)
    }
}

// MARK: - UIWebViewDelegate
extension FGOAuthViewController:UIWebViewDelegate {
    
    /// 将要加载请求
    ///
    /// - Parameters:
    ///   - webView: webView
    ///   - request: 要加载的请求
    ///   - navigationType:导航类型
    /// - Returns: 是否加载 request
    func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        
        // 1.如果请求地址包含 http://baidu.com 不加载页面 / 否则加载页面
        // equest.url?.absoluteString.hasPrefix(FGRedirectURL)返回的是可选项 true/false/nil
        if request.url?.absoluteString.hasPrefix(FGRedirectURL) == false {
            // 继续加载
            return true
        }
        // 2.从 http://baidu.com 回调地址的“查询字符串”中查找 ‘code=’
        // 如果有，授权成功，否则，授权失败(.query 表示取分隔符？后面的内容)
        if request.url?.query?.hasPrefix("code=") == false {
            print("取消授权")
            close()
            return false
        }
        // 3.从 query 字符串中取出授权码
        // 代码走到此处，URL 中一定有查询字符串，并且包含 ‘code=’
        let code = request.url?.query?.substring(from: "code=".endIndex) ?? ""
        print("授权码 - \(code)")
        
        // 4.使用授权码获取【换取】AccessToken
        FGNetworkManager.shared.loadAccessToken(code: code) { (isSuccess) in
            if !isSuccess {
                SVProgressHUD.showInfo(withStatus: "网络请求失败")
            } else {
                // 1> 通过通知发送登录成功消息,发送通知,不关心有没有监听者
                NotificationCenter.default.post(
                    name: NSNotification.Name(rawValue: FGUserLoginSuccessNotification),
                    object: nil)
                // 2> 关闭窗口
                self.close()
            }
        }
        
        return false
    }
    
    func webViewDidStartLoad(_ webView: UIWebView) {
        SVProgressHUD.show()
    }
    
    func webViewDidFinishLoad(_ webView: UIWebView) {
        SVProgressHUD.dismiss()
    }
}
